Heat exchanger



Nm- 4, 1958 M. EPHRAIM, JR., ETAL` 2,859,016

HEAT EXCHNGERA Filed Nov. 4, 195'? 2 Sheets-Sheet l O @mi m1,@

fw' ya www@ Nov. 4, 1958 M. EPHRAIM, JR., ETAL HEAT EXCHANGER y FiledNOV. 4, 195'? 2 Sheets-Sheet 2 IIN VEN T0 Rs A TTOR/VEV United StatesPatent O HEAT EXCHANGER Max Ephraim, Jr., Chicago, and John F. Novacek,Riverside, Ill., assignors to General Motors Corporation, Detroit,Mich., a Vcorporation of Delaware Application November 4, 1957, SerialNo. 694,064

2 Claims. (Cl. 257-227) This invention relates generally to heatexchangers and 'particularly to improvements in engine lubricating oilcoolers wherein the lubricating oil to be cooled flows in the `cooler atrelatively low velocities under light pressures. In heat exchangers withwhich the present invention is concerned there is provided a finnedheatV exchanging core past which the oil to be cooled must How. Suchheat exchangers have certain advantages over high pressure typesinasmuch as they do not require pressure vessels, external reliefvalves, or high pressure connections. Because of the low velocities andpressures, however, there isa tendency for the core to clog, eitherbecausetheoil is cold or because of sludge which collects on the core.

The present invention retains the advantages of lube oil coolerswhereinthe oil ows at relatively low velocities under relatively lightpressures and at the same time allows the oil to flow so asA to providecooling when there are substantial sludge deposits on the core tendingto prevent ow therethrough. This has been accomplished by providing insuch a cooler unique baiing means in combinationwith relatively lowpressure operated pressure relief valves which provide an alternativeeasier path for the oil past a part of the heat exchanging media used tocool the oil. Other objectives and advantages are attained |by theinvention which will be better understood by reference to theaccompanying detailed description and drawings in which:

Fig. 1 is a view in elevation with portions broken away and in sectionof the heat exchanger showing in detail certain of the features whichuniquely enhance the electiveness thereof.

Fig. 2 is a view in plan taken substantially on the line 2-2 of Fig. lillustrating particularly the unique pressure relief means utilized toallow continuous ow of lubricating oil through the heat exchangerregardless of the condition of the oil or the radiator core of the heatexchanger.

Fig.3 is a side view in elevation taken substantially on the line 3 3 ofFig. 1 further illustrating the details of construction including theunusual baiile means for directing the oil through the heat exchanger.

Fig. 4 is a fragmentary view in section taken substantially on the line4 4 of Fig. l greatly enlarged to illustrate one of the unique pressurerelief valves for allowing the oil to -by-pass the core of the radiatorof the heat exchanger when the oil is either too viscous to owtherethrough or the core is clogged by reason of sludge which is pickedup and carried thereto by the lubricating oil.

Referring now to the drawings, it will be observed that the heatexchanger which is indicated generally by a numeral 2 comprises an outercasing or container 4 which is closed at its lower end by a lower header6. The lower header 6 is provided with horizontally disposed inlet andoutlet chambers 8 and 10, respectively (see particularly Fig. 3).Lubricating oil which leaves an internal combustion engine is adapted tobe supplied from the engine through the oil inlet pipe 12 '(see Fig. 1)which leads into chamber 8. Oil leaves the heat exchanger via the outletchamber 10 and the pipe 14 which returns the now-cooled oil to theengine. Located within the container 4 is a radiator generally identiedby the numeral 16 which comprises -an upper header 18, a radiator core20 and a lower header 22. The lower header 22 is securely fastened tothe lower header 6 and cooperates therewith to vform the `area 24. Theupper header 18 of the radiator 16 defines an area 26 to which Water orother cooling media may Ibe supplied via the inlets 28 (see Fig. 1). The-upper and lower headers 18 and 22 of the radiator are placed in directcommunication with each othervby the core 20 which comprises nned tubessuch as 30, so that water or other cooling media may enter the inlets28, the area 26 of upper header 18, thence flow downwardly through thefinned tubes '30, to the area 24 of the lower header 22, and then out ofthe heat exchanger through the cooling media outlets 32. The radiatorassembly 16, which is made up as a unit as previously mentioned,V islsecurely fastened in place to the lower header 6 -by means of the studs34. This assembly as will best appear from Figures 1, 2, and 3 dividesthe volume in the container 4 into an inlet area 36 and an outlet area38 which are in communication with each other only through the core 16and over the top of the upper header 18 as at 40. Located within thearea 36 is an inlet baiile 42 which along its lower edge is clamped tothe lower header 6 by a flange 44 xedto the lower edge of the container4. The upper edge of baille 42 is sealingly connected to the upperheader 18 so that the inlet area 36 is actually divided into twoportions 46 and 48. The area 38 on the outlet side of the core 20 alsohas provided therein a baille 50 which has its lower edge sealinglyfixed to the lower header 22 of radiator 16 and a portion of' its upperedge fixed to the upper header 18. The baille 50, however, is providedwith a dam, the top of which is indicated by a numeral 52. Dam 52 allowsoil to spill over the top of baille 50 from a portion 54 of the area 38which is adjacent the outlet side of the core 20 into a second portion56. It will thus be appreciated that the bafes 42 and 50 together withthe upper and lower headers of the radiator 16 form a chamber 58 whichcontains the core 20. The inlet chamber 8 of the lower header 6 of theheat exchanger is in communication with the chamber S8 via passageway orport 60 which is -best seen in the lower lefthand corner of Fig. 3 inviewing the drawing. The area 56 which is located remote from the coreon its outlet side is in communication with the outlet chamber 10 of thelower header 6 via passageway or port 62.

Referring again for a moment to the inlet ybaille 42, it Will beobserved that this bailie is provided with a pair of horizontally spacedopenings 64 which are maintained normally closed by pressure reliefvalves 66 held on their seats 68 by a leaf spring 70 which is anchoredat the center thereof to the inlet balile 42 by means of the studs 72and has its ends 74 each connected to one of the valves 66 by the stud76.

The operation of the heat exchanger is as follows: The lubricating oilto be cooled is introduced from the engine into the pipe 12 and the oilinlet chamber 8. From chamber 8, the oil flows as indicated by thearrows into the chamber 48 which includes the core 20. The oil then owsthrough the core 20 where it gives up part of its heat to the coolingmedia flowing through the core. The oil is maintained built-up in thechamber 58 until it spills over the dam 52 into the area 56 whence itmay pass downwardly through port 62, through the oil outlet chamber 10and the piping 14 to return to the engine. Because of the very largefinned area of the tubes 20, the velocity of the oil flowing past thecore may be relatively low and still have adequate heat exchange. Thismeans that relatively low pressures will maintain this low oil flow as`long as the oil can flow rather freely through the core. However, ifthe oil is viscous, for example, due to the starting of a cold engine,there will be some resistance to flow which, if sufficient, will unseatthe pressure relief valves 66 thereby allowing the oil to flow upwardly,as indicated by the arrows in Figure 3, lover the topl of the upperheader 18` Sin-ce any type of uid heat exchanging medium cany vbe usedin the radiator 16 such medium can be provided to first heat the oilthereby making it less. viscous, thus a certain amount of heatexchanging may still occur although the core of the radiator is at leastpartially by-passed'. All this` has been accomplished without materiallyincreasing the pressures present inthe heat exchanger or the flow of oiltherethrough. The same by-passed path will-be followed inthe event thecore is clogged sufficiently `to cause the pressure relief valves 66 tounseat. It willbe noted that the area of the openings 64 is relativelylarge and that the path over the upper header ,18 isrelatively free fromobstructions so as to allow quite a free flowwof oil along such path inthe event the oil cannot freely fiow through the core 20. It will beappreciated, however, that even though a part or all of the oil takesthe alternative flow path, i. e., through the pressure relief valves andup over the top of the upper header 18, there still will be some heatlexchanging occurring as a result of the lubricating' oilv coming incontact with the upper header 18 in which heat exchanging medium isflowing.

From the foregoing it will be appreciated that a very effective lowvelocity, low pressure oil cooler has been provided which can handleboth hot and cold oil as well as oil containing substantial amounts ofsludge without the usual pressure problems encountered with moreconventional types of oil coolers.

We claim:

l. A heat exchanger comprising an outer container, a radiator includinga core and upper and lower headers dividing said container into an inletarea and an outlet area connected together through said core and oversaid upper header, an inlet baffle in said inlet area and an outletbaffle in said outlet area forming a chamber with said headers whichcontains said core, pressure relief means in said inlet bafe adapted toconnect that portion of the chamber which includes a portion of theinlet area with the rest of said inlet area and with said outlet areaover said upper header, said outlet baffle forming a darn in said outletarea adjacent said core over which fluid may flow into the rest of saidoutlet area, means for passing heat exchanging medium through saidradiator, means to-introduce heat exchanging medium to said portion, andmeans to remove saidlast-mentioned heat exchanging medium from the saidrest of said outlet area.

2. A lube oil cooler comprising an outer container having a lower headerforming the bottom thereof, said header having horizontally disposedinlet and outlet chambers for the introduction and egress of lubricatingoil, a radiator in said outer container including anupper header, acore, and a lower header which together with saidiirst.- mentioned lowerheader and the walls of said container form an inlet area and an outletarea in communication with said inlet and outlet chambers, respectively,said radiator preventing communication between said areas except throughsaid core and over said upper header, an inlet baie in said inlet areadirecting ow of oil through said core and including pressure reliefmeans to allow oil to flow over said upper header to saidl outlet area',a second baffle in said outlet area forming a dam adjacent said coreover which oil after passing through said core may iiow to thereby passinto said egress chamber, and' means for passing a heat exchangingmedium through said radiator.

References Cited in the file of this patent UNITED STATES PATENTS2,373,157 Worth Apr. 10; 1945 :FOREIGNy PATENTS 45,360 France May 6,1935

